We propose a new measure for explaining information search and compare it to the search index (SI, Payne, 1976), the most commonly used measure for exploring the pattern of search in process-tracing studies. The systematicity of search index (SSI) explores the pattern of search in terms of systematicity or the proportion of non- random search, i.e. search that is compensatory (alternative-wise) or noncompen- satory (attribute-wise) corrected for chance. The SI, on the other hand, shows the proportion of compensatory and noncompensatory search ignoring random search. We expect that the SSI will be higher in environments where information is visually organized compared to environments where it is disorganized. We test the SSI in a discrete choice experiment with four within-subjects conditions (compensatory, non- compensatory, matrix, and random matrix visual grouping) using eye tracking tech- nology. The results show a higher SSI in the matrix compared to the random matrix condition. The SI, however, is close to zero in both conditions. The compensatory and noncompensatory conditions show similar SSI, but differ on SI. Our experiment shows that the SSI is useful for calculating the amount of systematic search patterns in process-tracing studies and can shed light on processes not captured by the SI.